caleb moore was attempting a back flip when this happened. his snowmobile ski caught the snow. he slammed in the landing and the 450-pound machine crashed right over the top of him. at first he appeared to be okay. but after he was able to walk off the course medics rushed him to the hospital in colorado. that's where doctors found bleeding around his heart which reportedly caused complications in his brain. meanwhile caleb's brother colton separated his pelvis racing on the very same course. and on sunday another rider lost control of his snowmobile after a jump. we showed you this last night. the machine throttle somehow got stuck and zoomed toward a crowd of spectators. fortunately a net caught it just before it went into fans nearby. "the fox report's" chief correspondent jonathan hunt more with this night? do we know what went wrong. >> frankly, bill it, looks like a simple and yet disastrous mistake. 25-year-old caleb moore had landed this kind of trick many times before in practice and apparently in competition. trying to do a back flip. can you see there in slow motion.